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Departments & Programs


Differential Acoustic Spectroscopy (DARS)

Acoustical Resonance Spectroscopy (DARS) exploits the low frequency resonance
(~1000 Hz) of a fluid column to measure the bulk acoustic properties of a small
sample of rock and other material. First, we measure the resonant frequency
spectrum of a fluid-filled but otherwise empty cavity. Next, we introduce a
small sample of rock into the cavity and measure the changes in resonances,
both frequency and Q. The changes are then inverted to estimate the modulus and
Q of the sample. The first generation of DARS operates at atmospheric
pressure. The drawing above shows a new generation of DARS that measures
acoustic properties of a rock sample under high pressure.